BarBug Straight Up: COCKTAIL GLASS: Very versatile stemmed glass used for 'straight up' drinks like the cream drinks and martinis. Sizes range from 3 to 6 oz but the 4 oz is the most common size. The larger 6 ounce saucer style is used for margaritas and frozen drinks. The 4 oz 'V' shaped ones are commonly used for martinis.